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Daniel Nylander edited this page Aug 13, 2026 · 5 revisions

Save and Load

Documentation baseline: v1.1.126.

OpenCaptive uses two distinct binary save formats: OCSV for Captive and LSAV for Liberation.

Quick Reference

Action Key
Save (quicksave) F5
Load (quickload) F9
Cycle save slot F6

Captive Save Format (OCSV)

Captive saves use the OCSV binary format (version 3). The default file is opencaptive.sav, with 10 numbered slots: opencaptive_slot0.sav through opencaptive_slot9.sav.

Header

Offset  Size    Field
0x00    4       Magic: 0x4F435356 ("OCSV")
0x04    4       Version: 3
0x08    4       Game type (GAME_CAPTIVE or GAME_LIBERATION)
0x0C    4       Mission number
0x10    4       Mission seed
0x14    4       Base ID
0x18    4       Party X position (signed)
0x1C    4       Party Y position (signed)
0x20    4       Party direction (0-3)
0x24    4       Current level (signed)
0x28    4       Number of levels (signed)
0x2C    4       Generators total (signed)
0x30    4       Generators destroyed (signed)
0x34    4       Gold (signed)
0x38    4       Number of creatures (signed)
0x3C    4       Number of puzzles (signed)
0x40    4       Tick counter
0x44    4       Selected droid (0-3)

Body

After the header:

  1. Droids: 4 raw Droid structs (see Energy and Body Parts).
  2. Map cells: For each level (up to num_levels), MAP_HEIGHT (32) x MAP_WIDTH (64) bytes, one CellType byte per cell.
  3. Creatures: num_creatures creature records.
  4. Puzzles: num_puzzles puzzle records.

The format uses native endian (no byte swapping). The loader validates all fields strictly: magic must match, version must match, direction must be <= DIR_WEST, all counts must be non-negative and within bounds. Data is loaded into a temporary restored state and only committed on full success.

API

bool save_game(const GameState *gs, const CreatureList *creatures,
               const PuzzleList *puzzles, const char *path);
bool load_game(GameState *gs, CreatureList *creatures,
               PuzzleList *puzzles, const char *path);

Liberation Save Format (LSAV)

Liberation uses its own binary format with big-endian byte order (explicit MSB-first encoding via write_u16/write_u32).

Binary Layout

Offset  Size    Field
0x00    4       Magic: "LSAV" (ASCII)
0x04    2       Version: 1
0x06    2       Seed high word
0x08    2       Seed low word
0x0A    2       Difficulty
0x0C    2       Mission number
0x0E    4       Gold
0x12    4       Tick counter
0x16    2       City X position (signed)
0x18    2       City Y position (signed)
0x1A    1       Facing direction (0-3)
0x1B    1       Number of droids (max 4)

Droid Records (per droid)

Offset  Size    Field
+0x00   16      Name (null-terminated, padded)
+0x10   2       HP (signed)
+0x12   2       HP max (signed)
+0x14   2       Energy (signed)
+0x16   2       Energy max (signed)
+0x18   1       Level
+0x19   8       Skills (8 bytes)
+0x21   16      Equipment (8 x uint16)

Mission Complete Bitmap

After the droid records:

  • 32 bytes: a 256-bit bitmap tracking mission completion. Bit N is stored at byte N/8, bit position N%8.

Trailer

Offset  Size    Field
+0x00   2       Generators destroyed
+0x02   2       Generators total

API

bool lib_save_write(const LibSaveData *data, const char *path);
bool lib_save_read(LibSaveData *data, const char *path);
void lib_save_from_state(LibSaveData *data, const GameState *gs);
bool lib_save_is_mission_complete(const LibSaveData *data, int mission);
void lib_save_set_mission_complete(LibSaveData *data, int mission);

Continue from Menu

When the player selects Continue from the start menu, the most recent save file is loaded automatically. The menu checks for save file existence at startup via start_menu_check_saves.

Source Files

  • Captive save: include/save_load.h, src/engine/save_load.c
  • Liberation save: include/liberation_save.h, src/game/liberation_save.c

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